U.S. patent application number 13/641294 was filed with the patent office on 2013-03-21 for gas generation device and gas generation method.
This patent application is currently assigned to TOYO TANSO CO., LTD.. The applicant listed for this patent is Yoshio Shodai, Noriyuki Tanaka, Yasuhiro Yano, Osamu Yoshimoto. Invention is credited to Yoshio Shodai, Noriyuki Tanaka, Yasuhiro Yano, Osamu Yoshimoto.
Application Number | 20130068627 13/641294 |
Document ID | / |
Family ID | 44798446 |
Filed Date | 2013-03-21 |
United States Patent
Application |
20130068627 |
Kind Code |
A1 |
Shodai; Yoshio ; et
al. |
March 21, 2013 |
GAS GENERATION DEVICE AND GAS GENERATION METHOD
Abstract
A control device receives an output signal from a liquid level
sensor disposed in an anode chamber. This output signal indicates
whether the liquid level of the electrolytic bath in the anode
chamber is higher than a reference level. When the liquid level of
the electrolytic bath in the anode chamber is higher than the
reference level, the control device increases, by a prescribe
value, the frequency of a compressor driving voltage that is
generated in an inverter circuit. This increases the rotational
speed of a motor in the compressor, increases the discharge
pressure of hydrogen gas being discharged from the compressor, and
decreases the pressure inside the cathode chamber. As a result, the
liquid level of the electrolytic bath in the cathode chamber rises,
and the liquid level of the electrolytic bath in the anode chamber
falls below the reference level.
Inventors: |
Shodai; Yoshio; (Osaka,
JP) ; Yoshimoto; Osamu; (Kagawa, JP) ; Tanaka;
Noriyuki; (Osaka, JP) ; Yano; Yasuhiro;
(Kagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Shodai; Yoshio
Yoshimoto; Osamu
Tanaka; Noriyuki
Yano; Yasuhiro |
Osaka
Kagawa
Osaka
Kagawa |
|
JP
JP
JP
JP |
|
|
Assignee: |
TOYO TANSO CO., LTD.
OSAKA-SHI, OSAKA
JP
|
Family ID: |
44798446 |
Appl. No.: |
13/641294 |
Filed: |
March 23, 2011 |
PCT Filed: |
March 23, 2011 |
PCT NO: |
PCT/JP11/01709 |
371 Date: |
November 8, 2012 |
Current U.S.
Class: |
205/335 ;
204/228.2 |
Current CPC
Class: |
C25B 9/00 20130101; C25B
15/08 20130101; C25B 1/245 20130101 |
Class at
Publication: |
205/335 ;
204/228.2 |
International
Class: |
C25B 15/02 20060101
C25B015/02; C25B 9/04 20060101 C25B009/04 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 14, 2010 |
JP |
2010-093437 |
Claims
1. A gas generation device that generates a first gas and a second
gas by electrolysis, comprising: an electrolyzer divided into a
first chamber and a second chamber and containing therein an
electrolytic bath including a compound to be electrolyzed; a first
gas discharge path through which the first gas generated in said
first chamber is discharged; a second gas discharge path through
which the second gas generated in said second chamber is
discharged; a liquid level detector that detects a liquid level of
the electrolytic bath in said second chamber; a first pump having a
motor and provided on said first gas discharge path; a first
inverter circuit that generates a driving voltage to be applied to
the motor of said first pump; and a controller that controls said
first inverter circuit, in the case where the liquid level detected
by said liquid level detector is higher than a predetermined
reference level, such that at least one of an effective value and a
frequency of the driving voltage being applied to the motor of said
first pump increases.
2. The gas generation device according to claim 1, further
comprising a first pressure detector that detects a pressure inside
said first chamber, wherein in the case where the liquid level
detected by said liquid level detector is not higher than said
reference level, said controller controls at least one of an
effective value and a frequency of the driving voltage generated by
said first inverter circuit such that the pressure detected by said
first pressure detector approaches a first target value.
3. The gas generation device according to claim 1, further
comprising: a second pump having a motor and provided on said
second gas discharge path; a second inverter circuit that generates
a driving voltage to be applied to the motor of said second pump;
and a second pressure detector that detects a pressure inside said
second chamber, wherein said controller controls at least one of an
effective value and a frequency of the driving voltage generated by
said second inverter circuit such that the pressure detected by
said second pressure detector approaches a second target value.
4. The gas generation device according to claim 1, further
comprising: a first pressure detector that detects a pressure
inside said first chamber; a second pump having a motor and
provided on said second gas discharge path; a second inverter
circuit that generates a driving voltage to be applied to the motor
of said second pump; and a second pressure detector that detects a
pressure inside said second chamber, wherein in the case where the
liquid level detected by said liquid level detector is not higher
than said reference level, said controller controls at least one of
an effective value and a frequency of the driving voltage generated
by said first inverter circuit such that the pressure detected by
said first pressure detector approaches a first target value, and
also controls at least one of an effective value and a frequency of
the driving voltage generated by said second inverter circuit such
that the pressure detected by said second pressure detector
approaches a second target value that is smaller than said first
target value.
5. The gas generation device according to claim 1, further
comprising: a first open/close valve provided on said first gas
discharge path; and a second open/close valve provided on said
second gas discharge path, wherein said controller opens said first
and second open/close valves in the case where electrolysis is
carried out in said electrolyzer, and closes said first and second
open/close valves in the case where no electrolysis is carried out
in said electrolyzer.
6. The gas generation device according to claim 1, wherein said
first chamber is a cathode chamber, and said second chamber is an
anode chamber.
7. The gas generation device according to claim 1, wherein said
second gas is fluorine.
8. A gas generation method for generating a first gas and a second
gas by electrolysis by using an electrolyzer divided into a first
chamber and a second chamber, the method comprising the steps of:
generating the first and second gases in said first and second
chambers, respectively, by applying a voltage to an electrolytic
bath contained in said electrolyzer, and discharging the first and
second gases generated in said first and second chambers through
first and second gas discharge paths, respectively; controlling, by
a first pump having a motor, the discharge of the first gas through
said first gas discharge path; detecting a liquid level of the
electrolytic bath in said second chamber; applying a driving
voltage to the motor of said first pump by a first inverter
circuit; and in the case where said detected liquid level is higher
than a predetermined reference level, controlling said first
inverter circuit such that at least one of an effective value and a
frequency of the driving voltage being applied to the motor of said
first pump increases.
9. The gas generation method according to claim 8, further
comprising the steps of: detecting a pressure inside said first
chamber; in the case where said detected liquid level is not higher
than the predetermined reference level, controlling at least one of
an effective value and a frequency of the driving voltage generated
by said first inverter circuit such that said detected pressure
inside said first chamber approaches a first target value;
controlling, by a second pump having a motor, the discharge of the
second gas through said second gas discharge path; applying a
driving voltage to the motor of said second pump by a second
inverter circuit; detecting a pressure inside said second chamber;
and controlling at least one of an effective value and a frequency
of the driving voltage generated by said second inverter circuit
such that said detected pressure inside said second chamber
approaches a second target value that is smaller than said first
target value.
Description
TECHNICAL FIELD
[0001] The present invention relates to a gas generation device and
a gas generation method for generating a gas.
BACKGROUND ART
[0002] Conventionally, fluorine gas is used in the semiconductor
manufacturing process and so on for material cleaning, surface
modification, and other purposes. While the fluorine gas itself is
used in some cases, a variety of fluorine-based gases synthesized
based on the fluorine gas, such as NF.sub.3 (nitrogen trifluoride)
gas, NeF (neon fluoride) gas, and ArF (argon fluoride) gas, may
also be used in other cases.
[0003] For supplying fluorine gas stably in such sites, a fluorine
gas generation device that generates fluorine gas by electrolysis
of HF (hydrogen fluoride), for example, is used.
[0004] The fluorine gas generation device disclosed in Patent
Document 1 includes an electrolyzer. The interior of the
electrolyzer is divided by a partition wall into a cathode chamber
and an anode chamber. In the electrolyzer, an electrolytic bath is
formed with a KF-HF-based mixed molten salt. A cathode is disposed
in the cathode chamber, and an anode is disposed in the anode
chamber. HF is supplied through an HF supply line to the
electrolytic bath in the electrolyzer for electrolysis of HF,
whereby hydrogen gas is generated from the cathode and fluorine gas
is generated from the anode in the electrolyzer.
[0005] At the top of the cathode chamber, an outlet for hydrogen
gas is provided. The hydrogen gas generated in the cathode chamber
exits from the outlet and is discharged through a hydrogen gas line
on the cathode side. The hydrogen gas line is provided with an
automatic valve and an HF adsorption column. Further, at the top of
the cathode chamber, a purge gas inlet/outlet for supplying an
inert gas into the cathode chamber is provided. This allows the
inert gas to be supplied into the cathode chamber from an inert gas
line through the purge gas inlet/outlet. The inert gas line is also
provided with an automatic valve.
[0006] At the top of the anode chamber, an outlet for fluorine gas
is provided. The fluorine gas generated in the anode chamber exits
from the outlet and is discharged through a fluorine gas line. The
fluorine gas line is provided with an HF adsorption column and an
automatic valve. Furthermore, on the fluorine gas line, a
compressor unit is provided on the downstream of the HF adsorption
column and the automatic valve. Further, at the top of the anode
chamber, a purge gas inlet/outlet for supplying an inert gas into
the anode chamber is provided. This allows the inert gas to be
supplied also into the anode chamber from an inert gas line through
the purge gas inlet/outlet. This inert gas line is also provided
with an automatic valve.
[0007] In each of the cathode chamber and the anode chamber, a
liquid level sensor is provided which detects the liquid level of
the electrolytic bath in the corresponding chamber. The automatic
valves disposed on the hydrogen gas line, the fluorine gas line,
and the inert gas lines open/close in accordance with the liquid
levels of the electrolytic bath in the respective chambers detected
by the liquid level sensors. As the automatic valves open/close in
response to the liquid levels detected by the liquid level sensors,
fluctuations in liquid level of the electrolytic bath are
restricted, and accordingly, fluctuations in electrolysis
conditions upon electrolysis of HF are restricted. [0008] [Patent
Document 1] JP 2004-52105 A
SUMMARY OF INVENTION
Technical Problem
[0009] In order to restrict the fluctuations in liquid level of the
electrolytic bath, however, it is necessary to open/close the
automatic valves frequently. Particularly in the case where the
liquid level fluctuates constantly, the number of operations of
opening/closing the automatic valves per unit time increases. In
this case, the lives of the automatic valves are shortened, and the
maintenance (replacement, repair, etc.) of the automatic valves
needs to be performed frequently. This leads to an increase in
maintenance cost.
[0010] An object of the present invention is to provide a gas
generation device and a gas generation method capable of reducing
the maintenance cost while restricting the fluctuations in liquid
level of the electrolytic bath.
Solution to Problem
[0011] (1) According to an aspect of the present invention, a gas
generation device that generates a first gas and a second gas by
electrolysis includes an electrolyzer divided into a first chamber
and a second chamber and containing therein an electrolytic bath
including a compound to be electrolyzed, a first gas discharge path
through which the first gas generated in the first chamber is
discharged, a second gas discharge path through which the second
gas generated in the second chamber is discharged, a liquid level
detector that detects a liquid level of the electrolytic bath in
the second chamber, a first pump having a motor and provided on the
first gas discharge path, a first inverter circuit that generates a
driving voltage to be applied to the motor of the first pump, and a
controller that controls the first inverter circuit, in the case
where the liquid level detected by the liquid level detector is
higher than a predetermined reference level, such that at least one
of an effective value and a frequency of the driving voltage being
applied to the motor of the first pump increases.
[0012] In this gas generation device, electrolysis of the compound
included in the electrolytic bath is carried out, so that a first
gas is generated in the first chamber and a second gas is generated
in the second chamber.
[0013] The first gas generated in the first chamber is discharged
through the first gas discharge path by the first pump having a
motor. The second gas generated in the second chamber is discharged
through the second gas discharge path. The first pump operates as
the driving voltage generated by the first inverter circuit is
applied to the motor.
[0014] The liquid level of the electrolytic bath in the second
chamber is detected by the liquid level detector. In the case where
the detected liquid level is higher than a reference level, the
first inverter circuit is controlled such that at least one of the
effective value and frequency of the driving voltage being applied
to the motor of the first pump increases.
[0015] In this case, the rotational speed of the motor of the first
pump increases, and the discharge pressure of the first gas by the
first pump increases, so that the pressure inside the first chamber
decreases. As a result, the liquid level of the electrolytic bath
in the first chamber rises, and also, the liquid level of the
electrolytic bath in the second chamber is adjusted to a level not
higher than the reference level. In this manner, the fluctuations
in liquid level of the electrolytic bath are restricted.
[0016] Further, in the first gas discharge path, the discharge
pressure of the first gas is adjusted by changing the rotational
speed of the motor of the first pump. This eliminates the need to
adjust the discharge pressure of the first gas through the
operations of opening/closing the open/close valves. It is thus
unnecessary to perform maintenance due to the early deterioration
of the open/close valves, and the number of times of maintenance
work decreases. This results in a reduction of the maintenance cost
of the gas generation device.
[0017] (2) The gas generation device may further include a first
pressure detector that detects a pressure inside the first chamber,
and, in the case where the liquid level detected by the liquid
level detector is not higher than the reference level, the
controller may control at least one of an effective value and a
frequency of the driving voltage generated by the first inverter
circuit such that the pressure detected by the first pressure
detector approaches a first target value.
[0018] In this case, the pressure inside the first chamber is
detected by the first pressure detector. In the case where the
liquid level detected by the liquid level detector is not higher
than the reference level, at least one of the effective value and
frequency of the driving voltage generated by the first inverter
circuit is controlled such that the pressure detected by the first
pressure detector approaches the first target value.
[0019] This changes the rotational speed of the motor of the first
pump, and changes the discharge pressure of the first gas by the
first pump, whereby the pressure inside the first chamber is
adjusted to approach the first target value. Accordingly, it is
possible to restrict the fluctuations in pressure inside the first
chamber, while restricting the fluctuations in liquid level in the
second chamber.
[0020] (3) The gas generation device may further include a second
pump having a motor and provided on the second gas discharge path,
a second inverter circuit that generates a driving voltage to be
applied to the motor of the second pump, and a second pressure
detector that detects a pressure inside the second chamber, and the
controller may control at least one of an effective value and a
frequency of the driving voltage generated by the second inverter
circuit such that the pressure detected by the second pressure
detector approaches a second target value.
[0021] In this case, the second gas generated in the second chamber
is discharged through the second gas discharge path by the second
pump having a motor. The second pump operates as the driving
voltage generated by the second inverter circuit is applied to the
motor.
[0022] The pressure inside the second chamber is detected by the
second pressure detector. At least one of the effective value and
frequency of the driving voltage generated by the second inverter
circuit is controlled such that the pressure detected by the second
pressure detector approaches the second target value.
[0023] This changes the rotational speed of the motor of the second
pump, and changes the discharge pressure of the second gas by the
second pump, whereby the pressure inside the second chamber is
adjusted to approach the second target value. Accordingly, it is
possible to restrict the fluctuations in pressure inside the second
chamber, while restricting the fluctuations in liquid level in the
second chamber.
[0024] (4) The gas generation device may further include a first
pressure detector that detects a pressure inside the first chamber,
a second pump having a motor and provided on the second gas
discharge path, a second inverter circuit that generates a driving
voltage to be applied to the motor of the second pump, and a second
pressure detector that detects a pressure inside the second
chamber, and, in the case where the liquid level detected by the
liquid level detector is not higher than the reference level, the
controller may control at least one of an effective value and a
frequency of the driving voltage generated by the first inverter
circuit such that the pressure detected by the first pressure
detector approaches a first target value, and may also control at
least one of an effective value and a frequency of the driving
voltage generated by the second inverter circuit such that the
pressure detected by the second pressure detector approaches a
second target value that is smaller than the first target
value.
[0025] In this case, the pressure inside the first chamber is
detected by the first pressure detector. In the case where the
liquid level detected by the liquid level detector is not higher
than the reference level, at least one of the effective value and
frequency of the driving voltage generated by the first inverter
circuit is controlled such that the pressure detected by the first
pressure detector approaches the first target value.
[0026] This changes the rotational speed of the motor of the first
pump, and changes the discharge pressure of the first gas by the
first pump, whereby the pressure inside the first chamber is
adjusted to approach the first target value. Accordingly, it is
possible to restrict the fluctuations in pressure inside the first
chamber, while restricting the fluctuations in liquid level in the
second chamber.
[0027] Further, the second gas generated in the second chamber is
discharged through the second gas discharge path by the second pump
having a motor. The second pump operates as the driving voltage
generated by the second inverter circuit is applied to the
motor.
[0028] The pressure inside the second chamber is detected by the
second pressure detector. At least one of the effective value and
frequency of the driving voltage generated by the second inverter
circuit is controlled such that the pressure detected by the second
pressure detector approaches the second target value.
[0029] This changes the rotational speed of the motor of the second
pump, and changes the discharge pressure of the second gas by the
second pump, whereby the pressure inside the second chamber is
adjusted to approach the second target value. Accordingly, it is
possible to restrict the fluctuations in pressure inside the second
chamber, while restricting the fluctuations in liquid level in the
second chamber.
[0030] The second target value is smaller than the first target
value. In this case, the pressures inside the first and second
chambers are adjusted to approach the first and second target
values, respectively, and accordingly, the pressure inside the
second chamber becomes lower than the pressure inside the first
chamber. This prevents the liquid level of the electrolytic bath in
the first chamber from rising beyond the liquid level of the
electrolytic bath in the second chamber.
[0031] (5) The gas generation device may further include a first
open/close valve provided on the first gas discharge path, and a
second open/close valve provided on the second gas discharge path,
and the controller may open the first and second open/close valves
in the case where electrolysis is carried out in the electrolyzer,
and may close the first and second open/close valves in the case
where no electrolysis is carried out in the electrolyzer.
[0032] In this case, the first and second open/close valves are
opened when electrolysis takes place in the electrolyzer, while the
first and second open/close valves are closed when no electrolysis
takes place in the electrolyzer.
[0033] This allows the first gas generated in the first chamber to
be discharged through the first gas discharge path when
electrolysis is carried out in the electrolyzer. This also allows
the second gas generated in the second chamber to be discharged
through the second gas discharge path.
[0034] On the other hand, when no electrolysis is carried out in
the electrolyzer, the atmosphere outside the gas generation device
is prevented from flowing into the first chamber through the first
gas discharge path. And the atmosphere outside the gas generation
device is prevented from flowing into the second chamber through
the second gas discharge path.
[0035] (6) The first chamber may be a cathode chamber, and the
second chamber may be an anode chamber.
[0036] In this case, the liquid level of the electrolytic bath in
the anode chamber is detected by the liquid level detector. In the
case where the detected liquid level is higher than the reference
level, the first inverter circuit is controlled such that at least
one of the effective value and frequency of the driving voltage
being applied to the motor of the first pump increases.
[0037] This increases the rotational speed of the motor of the
first pump, and increases the discharge pressure of the first gas
by the first pump, whereby the pressure inside the anode chamber
decreases. As a result, the liquid level of the electrolytic bath
in the anode chamber rises, and also, the liquid level of the
electrolytic bath in the cathode chamber is adjusted to a level not
higher than the reference level.
[0038] (7) The second gas may be fluorine. In the second chamber
where fluorine is generated, the liquid level of the electrolytic
bath is likely to rise at the time of electrolysis of the compound.
Even in such a case, the fluctuations in liquid level of the
electrolytic bath in the second chamber are restricted, which
ensures a stable supply of fluorine.
[0039] (8) According to another aspect of the present invention, a
gas generation method for generating a first gas and a second gas
by electrolysis by using an electrolyzer divided into a first
chamber and a second chamber includes the steps of generating the
first and second gases in the first and second chambers,
respectively, by applying a voltage to an electrolytic bath
contained in the electrolyzer, and discharging the first and second
gases generated in the first and second chambers through first and
second gas discharge paths, respectively, controlling, by a first
pump having a motor, the discharge of the first gas through the
first gas discharge path, detecting a liquid level of the
electrolytic bath in the second chamber, applying a driving voltage
to the motor of the first pump by a first inverter circuit, and in
the case where the detected liquid level is higher than a
predetermined reference level, controlling the first inverter
circuit such that at least one of an effective value and a
frequency of the driving voltage being applied to the motor of the
first pump increases.
[0040] In this gas generation method, a voltage is applied to the
electrolytic bath contained in the electrolyzer, so that a first
gas is generated in the first chamber and a second gas is generated
in the second chamber. The first and second gases generated in the
first and second chambers are discharged through the first and
second gas discharge paths, respectively. The discharge of the
first gas through the first gas discharge path is controlled by the
first pump having a motor. The first pump operates as a driving
voltage is applied to the motor by the first inverter circuit.
[0041] The liquid level of the electrolytic bath in the second
chamber is detected. In the case where the detected liquid level is
higher than a reference level, the first inverter circuit is
controlled such that at least one of the effective value and
frequency of the driving voltage being applied to the motor of the
first pump increases.
[0042] In this case, the rotational speed of the motor of the first
pump increases, and the discharge pressure of the first gas by the
first pump increases, so that the pressure inside the first chamber
decreases. As a result, the liquid level of the electrolytic bath
in the first chamber rises, and also, the liquid level of the
electrolytic bath in the second chamber is adjusted to a level not
higher than the reference level. In this manner, the fluctuations
in liquid level of the electrolytic bath are restricted.
[0043] Further, in the first gas discharge path, the discharge
pressure of the first gas is adjusted by changing the rotational
speed of the motor of the first pump. This eliminates the need to
adjust the discharge pressure of the first gas through the
operations of opening/closing the open/close valves. It is thus
unnecessary to perform maintenance due to the early deterioration
of the open/close valves, and the number of times of maintenance
work decreases. This results in a reduction of the maintenance cost
of the gas generation device.
[0044] (9) The gas generation method may further include the steps
of detecting a pressure inside the first chamber, in the case where
the detected liquid level is not higher than the predetermined
reference level, controlling at least one of an effective value and
a frequency of the driving voltage generated by the first inverter
circuit such that the detected pressure inside the first chamber
approaches a first target value, controlling, by a second pump
having a motor, the discharge of the second gas through the second
gas discharge path, applying a driving voltage to the motor of the
second pump by a second inverter circuit, detecting a pressure
inside the second chamber, and controlling at least one of an
effective value and a frequency of the driving voltage generated by
the second inverter circuit such that the detected pressure inside
the second chamber approaches a second target value that is smaller
than the first target value.
[0045] In this case, the pressure inside the first chamber is
detected. In the case where the detected liquid level is not higher
than the reference level, at least one of the effective value and
frequency of the driving voltage generated by the first inverter
circuit is controlled such that the detected pressure approaches
the first target value.
[0046] This changes the rotational speed of the motor of the first
pump, and changes the discharge pressure of the first gas by the
first pump, whereby the pressure inside the first chamber is
adjusted to approach the first target value. Accordingly, it is
possible to restrict the fluctuations in pressure inside the first
chamber, while restricting the fluctuations in liquid level in the
second chamber.
[0047] The second gas generated in the second chamber is discharged
through the second gas discharge path by the second pump having a
motor. The second pump operates as the driving voltage generated by
the second inverter circuit is applied to the motor.
[0048] The pressure inside the second chamber is detected. At least
one of the effective value and frequency of the driving voltage
generated by the second inverter circuit is controlled such that
the detected pressure approaches the second target value.
[0049] This changes the rotational speed of the motor of the second
pump, and changes the discharge pressure of the second gas by the
second pump, whereby the pressure inside the second chamber is
adjusted to approach the second target value. Accordingly, it is
possible to restrict the fluctuations in pressure inside the second
chamber, while restricting the fluctuations in liquid level in the
second chamber.
[0050] The second target value is smaller than the first target
value. In this case, the pressures inside the first and second
chambers are adjusted to approach the first and second target
values, respectively, and accordingly, the pressure inside the
second chamber becomes lower than the pressure inside the first
chamber. This prevents the liquid level of the electrolytic bath in
the first chamber from rising beyond the liquid level of the
electrolytic bath in the second chamber.
Advantageous Effects of Invention
[0051] According to the present invention, it is possible to reduce
the maintenance cost while restricting the fluctuations in liquid
level of the electrolytic bath.
BRIEF DESCRIPTION OF DRAWINGS
[0052] FIG. 1 is a schematic diagram showing the configuration of a
fluorine gas generation device according to an embodiment of the
present invention.
[0053] FIG. 2 is a block diagram showing a part of a control system
in the fluorine gas generation device in FIG. 1.
[0054] FIG. 3 shows graphs illustrating specific examples of liquid
level control and pressure control.
[0055] FIG. 4 is a flowchart illustrating a series of processes of
electrolysis using the liquid level control and the pressure
control.
[0056] FIG. 5 is a flowchart illustrating a series of processes of
electrolysis using the liquid level control and the pressure
control.
[0057] FIG. 6 is a schematic diagram showing the configuration of
the fluorine gas generation device according to another
embodiment.
[0058] FIG. 7 is a schematic diagram showing the configuration of
the fluorine gas generation device according to yet another
embodiment.
DESCRIPTION OF EMBODIMENTS
[0059] A gas generation device and a gas generation method
according to an embodiment of the present invention will now be
described with reference to the drawings. In the following
embodiment, a fluorine gas generation device for generating
fluorine gas will be described as an example of the gas generation
device.
(1) Configuration of the Fluorine Gas Generation Device
[0060] FIG. 1 is a schematic diagram showing the configuration of
the fluorine gas generation device according to an embodiment of
the present invention. As shown in FIG. 1, the fluorine gas
generation device 100 includes an electrolyzer 1. The electrolyzer
1 is formed, for example, of Ni (nickel), Monel, pure iron,
stainless steel, or other metal or alloy. The interior of the
electrolyzer 1 is divided by a partition wall 2 into a cathode
chamber 3 and an anode chamber 4. The partition wall 2 is made of
Ni or Monel, for example.
[0061] In the electrolyzer 1, an electrolytic bath 5 of KF-HF-based
mixed molten salt is formed. A cathode 6 of Ni (nickel), for
example, is disposed in the cathode chamber 3, and an anode 7 of
carbon with low polarizability, for example, is disposed in the
anode chamber 4. As HF (hydrogen fluoride) is supplied through an
HF supply pipe 10 to the electrolytic bath 5 in the electrolyzer 1,
electrolysis of HF takes place. As a result, in the electrolyzer 1,
hydrogen gas is primarily generated from the cathode 6 and fluorine
gas is primarily generated from the anode 7.
[0062] At the top of the cathode chamber 3, a cathode outlet 20a is
provided. Connected to the cathode outlet 20a is an (upstream) end
of a hydrogen gas discharge pipe 20. The hydrogen gas generated in
the cathode chamber 3 exits from the cathode outlet 20a and is
discharged through the hydrogen gas discharge pipe 20. The hydrogen
gas discharge pipe 20 has an HF adsorption column 24, a control
valve 21, a compressor 22, and a control valve 23 provided in this
order from the upstream to the downstream.
[0063] The HF adsorption column 24 is packed with NaF or the like.
The HF adsorption column 24 serves to adsorb HF within a mixture of
HF and hydrogen gas that is discharged from the cathode chamber 3.
The compressor 22 is connected with an inverter circuit 22I. A
driving voltage generated by the inverter circuit 22I is applied to
the compressor 22.
[0064] The hydrogen gas discharge pipe 20 has its downstream end
connected, for example, to an exhaust line in a factory. This
allows the hydrogen gas discharged from the cathode chamber 3 to be
discharged through the factory exhaust line.
[0065] At the top of the anode chamber 4, an anode outlet 30a is
provided. Connected to the anode outlet 30a is an (upstream) end of
a fluorine gas discharge pipe 30. The fluorine gas generated in the
anode chamber 4 exits from the anode outlet 30a and is discharged
through the fluorine gas discharge pipe 30. The fluorine gas
discharge pipe 30 has an HF adsorption column 34, a control valve
31, a compressor 32, and a control valve 33 provided in this order
from the upstream to the downstream.
[0066] The HF adsorption column 34 is packed with NaF or the like.
The HF adsorption column 34 serves to adsorb HF within a mixture of
HF and fluorine gas that is discharged from the anode chamber 4.
The compressor 32 is connected with an inverter circuit 32I. A
driving voltage generated by the inverter circuit 32I is applied to
the compressor 32.
[0067] The fluorine gas discharge pipe 30 has its downstream end
connected, for example, to a manufacturing line in a factory. This
allows the fluorine gas discharged from the anode chamber 4 to be
supplied, at a predetermined flow rate, to the factory
manufacturing line or the like.
[0068] The cathode chamber 3 is provided with a pressure gauge PS1
that measures the pressure inside the cathode chamber 3. The anode
chamber 4 is provided with a pressure gauge PS2 that measures the
pressure inside the anode chamber 4. The anode chamber 4 is further
provided with a liquid level sensor 40 that detects the liquid
level of the electrolytic bath 5 in the anode chamber 4.
[0069] The HF supply pipe 10 is provided with an automatic valve 11
and an orifice 12. In order to prevent the electrolytic bath 5 from
being sucked into the HF supply pipe 10, a control valve 13 is
connected between the hydrogen gas discharge pipe 20 and the HF
supply pipe 10 on the downstream of the orifice 12. It is noted
that the HF supply pipe 10 is provided with a pressure gauge (not
shown).
[0070] In the present embodiment, the compressors 22, 32 are
bellows compressors that respectively include metal bellows and
motors 22M, 23M (FIG. 2), which will be described later. During the
operations of the compressors 22, 32, the metal bellows are
expanded/contracted by the motors 22M, 23M. The amounts of
expansion/contraction as well as the cycles of expansion and
contraction of the respective bellows at that time can be adjusted
so as to adjust the discharge pressures of the gases (hydrogen gas
and fluorine gas) by the compressors 22, 23. It is noted that the
amount of expansion/contraction of the bellows refers to the
difference between the length of the bellows in the most expanded
state and the length of the bellows in the most contracted
state.
(2) Control System in the Fluorine Gas Generation Device
[0071] A control device 90 includes a central processing unit (CPU)
and a memory, or a microcomputer. The control device 90 controls
the operations of the elements constituting the fluorine gas
generation device 100.
[0072] FIG. 2 is a block diagram showing a part of a control system
in the fluorine gas generation device 100 in FIG. 1. As shown in
FIG. 2, the control device 90 receives an output signal from the
liquid level sensor 40 disposed in the anode chamber 4. This output
signal indicates whether the liquid level of the electrolytic bath
5 in the anode chamber 4 is higher than a predetermined liquid
level (hereinafter, referred to as the "reference level"). The
control device 90 controls the inverter circuit 22I on the basis of
the output signal from the liquid level sensor 40.
[0073] More specifically, in the case where the liquid level of the
electrolytic bath 5 in the anode chamber 4 is higher than the
reference level, the control device 90 increases the frequency of
the driving voltage, generated in the inverter circuit 22I, by a
prescribed value (of not less than 10 Hz and not more than 20 Hz,
for example). This increases the rotational speed of the motor 22M
included in the compressor 22, and shortens the cycle of expansion
and contraction of the bellows, and accordingly, the discharge
pressure of the hydrogen gas discharged from the compressor 22
increases, and the pressure inside the cathode chamber 3 decreases.
As a result, the liquid level of the electrolytic bath 5 in the
cathode chamber 3 rises, and the liquid level of the electrolytic
bath 5 in the anode chamber 4 falls below the reference level.
[0074] On the other hand, in the case where the liquid level of the
electrolytic bath 5 in the anode chamber 4 is not higher than the
reference level, the control device 90 refrains from increasing the
frequency of the driving voltage of the compressor 22, generated in
the inverter circuit 22I, by the prescribed value described
above.
[0075] In this manner, when the liquid level of the electrolytic
bath 5 in the anode chamber 4 rises beyond the reference level, the
control device 90 controls the inverter circuit 22I such that the
liquid level falls to the reference level or below.
[0076] In the following description, the control of the inverter
circuit 22I based on the output signal from the liquid level sensor
40 performed by the control device 90 will be referred to as
"liquid level control."
[0077] While the description was made above about the case where
the liquid level control is performed by changing the frequency of
the driving voltage generated in the inverter circuit 22I, the
liquid level control may be performed by changing an effective
value of the driving voltage generated in the inverter circuit 22I.
In this case, the discharge pressure of the hydrogen gas discharged
from the compressor 22 is controlled in accordance with a change in
the amount of expansion/contraction of the bellows, whereby the
pressure inside the cathode chamber 3 is changed. As a result, the
liquid level of the electrolytic bath 5 in the cathode chamber 3
changes, and the liquid level in the anode chamber 4 is
adjusted.
[0078] The liquid level control may also be performed by changing
both of the effective value and frequency of the driving voltage
generated in the inverter circuit 22I. As the amount of
expansion/contraction and the cycle of expansion and contraction of
the bellows change, the discharge pressure of the hydrogen gas
discharged from the compressor 22 is controlled, so that the
pressure inside the cathode chamber 3 is changed. As a result, the
liquid level of the electrolytic bath 5 in the cathode chamber 3
changes, and the liquid level in the anode chamber 4 is
adjusted.
[0079] The control device 90 also receives an output signal from
the pressure gauge PS1 disposed in the cathode chamber 3. The
control device 90 controls at least one of the effective value and
frequency of the driving voltage generated in the inverter circuit
22I on the basis of the output signal from the pressure gauge PS1.
As a result, the pressure inside the cathode chamber 3 is
adjusted.
[0080] For example, in the case where the value of the pressure
inside the cathode chamber 3 (hereinafter, referred to as the
"cathode chamber pressure value") measured by the pressure gauge
PS1 at the time of electrolysis of HF does not agree with a
prescribed value (target pressure value), the control device 90
controls the inverter circuit 22I such that the difference between
the cathode chamber pressure value and the target pressure value
decreases. It is noted that the target pressure value is set, for
example, to 100 kPa in absolute pressure.
[0081] Furthermore, the control device 90 receives an output signal
from the pressure gauge PS2 disposed in the anode chamber 4. The
control device 90 controls at least one of an effective value and a
frequency of the driving voltage generated in the inverter circuit
32I on the basis of the output signal from the pressure gauge PS2.
As a result, the pressure inside the anode chamber 4 is
adjusted.
[0082] For example, in the case where the value of the pressure
inside the anode chamber 4 (hereinafter, referred to as the "anode
chamber pressure value") measured by the pressure gauge PS2 at the
time of electrolysis of HF does not agree with a prescribed value
(target pressure value), the control device 90 controls the
inverter circuit 32I such that the difference between the anode
chamber pressure value and the target pressure value decreases. It
is noted that the target pressure value is set, for example, to 100
kPa in absolute pressure.
[0083] In the following description, the control of the inverter
circuits 22I, 32I based on the output signals from the pressure
gauges PS1, PS2 performed by the control device 90 will be referred
to as "pressure control."
[0084] The control device 90 opens the control valves 21, 23, 31,
33 while electrolysis of HF is taking place, whereas the control
device 90 closes the control valves 21, 23, 31, 33 while no
electrolysis of HF is taking place. This prevents the hydrogen gas
or the fluorine gas downstream of the compressor 22, 32 from being
sucked into the cathode chamber 3 or the anode chamber 4 while no
electrolysis of HF is taking place. The control device 90 also
controls the opening/closing of the control valve 13.
[0085] As described above, in this fluorine gas generation device
100, in the case where the liquid level of the electrolytic bath 5
in the anode chamber 4 becomes higher than the reference level, the
inverter circuit 22I is controlled such that the liquid level falls
to the reference level or below, for the following reason.
[0086] In the case of conducting electrolysis of HF in the
electrolyzer 1 shown in FIG. 1, the liquid level of the
electrolytic bath 5 in the anode chamber 4 is likely to rise
compared to the liquid level of the electrolytic bath 5 in the
cathode chamber 3. Therefore, in the present embodiment, the
inverter circuit 22I is controlled on the basis of the output
signal from the liquid level sensor 40 such that, when the liquid
level of the electrolytic bath 5 in the anode chamber 4 has risen
beyond the reference level, the liquid level is adjusted to fall to
the reference level or below, for restricting the fluctuations in
liquid level.
[0087] In the liquid level control, the inverter circuit 22I is
controlled, for the following reason.
[0088] As previously described, in the fluorine gas generation
device 100 in FIG. 1, the fluorine gas discharged from the anode
chamber 4 is supplied through the fluorine gas discharge pipe 30 to
the manufacturing line in a factory or the like at a predetermined
flow rate. Therefore, it is preferable that the discharge pressure
of the fluorine gas discharged from the compressor 32 is maintained
approximately constant.
[0089] Therefore, in the present embodiment, the inverter circuit
22I is controlled so as to change the discharge pressure of the
compressor 22 disposed on the hydrogen gas discharge pipe 20. This
allows the liquid level of the electrolytic bath 5 in the anode
chamber 4 to be adjusted to the reference level or below, without
causing large fluctuations in the flow rate of the fluorine gas
discharged from the fluorine gas discharge pipe 30.
(3) Specific Examples of Liquid Level Control and Pressure
Control
[0090] FIG. 3 shows graphs illustrating specific examples of the
liquid level control and the pressure control. FIG. 3(a) shows the
rotational speeds of the motors 22M, 32M when the liquid level
control and the pressure control are carried out. In FIG. 3(a), the
vertical axis represents rotational speed, and the horizontal axis
represents time. Further, the bold solid line represents the
rotational speed of the motor 22M, and the long dashed dotted line
represents the rotational speed of the motor 32M.
[0091] Further, FIG. 3(b) shows the cathode chamber pressure value
and the anode chamber pressure value when the liquid level control
and the pressure control are carried out. In FIG. 3(b), the
vertical axis represents pressure, and the horizontal axis
represents time. Further, the bold broken line represents the
cathode chamber pressure value, and the solid line represents the
anode chamber pressure value.
[0092] At time t0, electrolysis of HF is initiated, with the liquid
level of the electrolytic bath 5 in the anode chamber 4 being not
higher than the reference level. In the case where the liquid level
of the electrolytic bath 5 is maintained at the reference level or
below from time t0 to time t1, the control device 90 controls the
inverter circuits 22I, 32I on the basis of the output signals from
the pressure gauges PS1, PS2 (FIG. 1) (pressure control).
[0093] As such, as shown in FIG. 3(a), during the period PP in
which the liquid level of the electrolytic bath 5 is not higher
than the reference level, the inverter circuits 22I, 32I are
controlled in accordance with the fluctuations of the cathode
chamber pressure value and the anode chamber pressure value, which
results in gradual changes of the rotational speeds of the motors
22M, 32M. In this manner, the pressure inside the cathode chamber 3
and the pressure inside the anode chamber 4 are both adjusted to
approach a target pressure value U.
[0094] In the case where the liquid level of the electrolytic bath
5 continues to be higher than the reference level from time t1 to
time t2, during this period LP, the frequency of the driving
voltage of the compressor 22, generated in the inverter circuit
22I, is maintained at a value increased by a prescribed value T
with respect to the frequency at time t1 (liquid level control).
This causes the liquid level of the electrolytic bath 5 to be
adjusted to fall to the reference level or below. It is noted that
the prescribed value T is set to the order of not less than 5 Hz
and not more than 15 Hz, for example.
[0095] At time t2, when the liquid level of the electrolytic bath 5
falls to the reference level or below, the frequency of the driving
voltage, generated in the inverter circuit 22I, is decreased by the
prescribed value T with respect to the frequency at that time t2.
As a result, as shown in FIG. 3(a), the rotational speed of the
motor 22M steeply drops by the prescribed value T from time t2, so
that it becomes approximately the same as the rotational speed at
the start point (time t1) of that period LP.
[0096] In the example shown in FIG. 3, after the time t2, the
liquid level becomes higher than the reference level during the
periods from time t3 to time t4, from time t5 to time t6, and from
time t7 to time t8. In each of these periods LP as well, the
frequency of the driving voltage generated in the inverter circuit
22I is maintained at a level increased by the prescribed value T
with respect to the frequency at the start point (time t3, t5, t7)
of each period LP (liquid level control). In this manner, the
liquid level of the electrolytic bath 5 is adjusted to fall to the
reference level or below.
[0097] It is noted that during the periods LP described above, the
control device 90 continues to control the inverter circuit 32I on
the basis of the output signals from the pressure gauge PS2 (FIG.
1) (pressure control). Thus, as shown in FIG. 3(a), the rotational
speed of the motor 32M shows gradual changes during the periods LP
as well.
[0098] As in the period PP from time t0 to time t1, in each of the
periods PP from time t2 to time t3, from time t4 to time t5, and
from time t6 to time t7 where the liquid level of the electrolytic
bath 5 in the anode chamber 4 is not higher than the reference
level, the inverter circuits 22I, 32I are controlled in accordance
with the fluctuations of the cathode chamber pressure value and the
anode chamber pressure value. As a result, as shown in FIG. 3(b),
in each period PP, the cathode chamber pressure value gradually
approaches the target pressure value U, and the anode chamber
pressure value also gradually approaches the target pressure value
U.
[0099] As described above, by the liquid level control and the
pressure control performed by the control device 90, the
fluctuations in liquid level of the electrolytic bath 5 are
restricted and, at the same time, the fluctuations in pressure
inside the cathode chamber 3 and the anode chamber 4 are
restricted.
(4) Control Flow
[0100] FIGS. 4 and 5 show a flowchart illustrating a series of
processes of electrolysis using the liquid level control and the
pressure control. In the following, the control of the inverter
circuit 22I by the control device 90 will be described. In the
initial state, the compressors 22, 32 are operating at prescribed
rotational speeds in advance.
[0101] First, when the start of electrolysis of HF is instructed by
an input device (not shown) or the like, the control device 90
applies a prescribed voltage across the cathode 6 and the anode 7
(step S1), and opens two control valves 21, 23 disposed on the
hydrogen gas discharge pipe 20 (step S2).
[0102] Next, the control device 90 determines, on the basis of the
output signal from the liquid level sensor 40, whether the liquid
level of the electrolytic bath 5 in the anode chamber 4 is higher
than a reference level (step S3).
[0103] If the liquid level is higher than the reference level, the
control device 90 controls the inverter circuit 22I to increase the
rotational speed of the motor 22M by a prescribed value T (step
S4). For example, the control device 90 increases the frequency of
the driving voltage of the compressor 22, generated in the inverter
circuit 22I, by a prescribed value from the current frequency, to
thereby increase the rotational speed of the motor 22M by the
prescribed value T.
[0104] The control device 90 then determines, on the basis of the
output signal from the liquid level sensor 40, whether the liquid
level of the electrolytic bath 5 in the anode chamber 4 is higher
than the reference level (step S5). This step is repeated until the
liquid level falls to the reference level or below. Thereafter,
when the liquid level becomes not higher than the reference level,
the control device 90 controls the inverter circuit 22I to decrease
the rotational speed of the motor 22M by the prescribed value T
(step S6). The process then returns to step S3.
[0105] If it is determined in step S3 that the liquid level is not
higher than the reference level, the control device 90 acquires a
cathode chamber pressure value measured by the pressure gauge PS1
(step S7).
[0106] Here, in the control device 90, a target pressure value U
for the cathode chamber 3 is stored in advance. The target pressure
value U is set, for example, by an operator through manipulation of
an input device or the like.
[0107] The control device 90 determines whether the acquired
cathode chamber pressure value agrees with the preset target
pressure value U (step S8).
[0108] If the cathode chamber pressure value agrees with the target
pressure value U, the control device 90 controls the inverter
circuit 22I in FIG. 2 to maintain the rotational speed of the motor
22M at the current value (step S9). For example, the control device
90 maintains the frequency of the driving voltage generated in the
inverter circuit 22I at the current value, to thereby maintain the
rotational speed of the motor 22M.
[0109] If the cathode chamber pressure value does not agree with
the target pressure value U, the control device 90 changes the
rotational speed of the motor 22M by controlling the inverter
circuit 22I such that the difference between the cathode chamber
pressure value and the target pressure value U decreases (step
S10). For example, the control device 90 changes the frequency of
the driving voltage generated in the inverter circuit 22I from the
current value such that the difference between the cathode chamber
pressure value and the target pressure value U decreases, to
thereby change the rotational speed of the motor 22M.
[0110] For example, in the case where the cathode chamber pressure
value is lower than the target pressure value U, the control device
90 controls the inverter circuit 22I such that the driving voltage
applied to the motor 22M decreases. This reduces the rotational
speed of the motor 22M, and decreases the discharge pressure of the
compressor 22. As a result, the cathode chamber pressure value
increases to approach the target pressure value U, whereby the
difference between the cathode chamber pressure value and the
target pressure value U decreases.
[0111] Conversely, in the case where the cathode chamber pressure
value is higher than the target pressure value U, the control
device 90 controls the inverter circuit 22I such that the driving
voltage applied to the motor 22M increases. This increases the
rotational speed of the motor 22M, and increases the discharge
pressure of the compressor 22. As a result, the cathode chamber
pressure value decreases to approach the target pressure value U,
whereby the difference between the anode chamber pressure value and
the target pressure value U decreases.
[0112] After the processing in step S9 or S10, the control device
90 determines whether an end of the electrolysis of HF has been
instructed by an input device or the like (step S11). If the end of
electrolysis has not been instructed, the control device 90 returns
to the processing in step S3. On the other hand, if the end of
electrolysis has been instructed, the control device 90 stops
applying the voltage across the cathode 6 and the anode 7 (step
S12), and closes the two control valves 21, 23 disposed on the
hydrogen gas discharge pipe 20 (step S13). This terminates the
electrolysis of HF.
[0113] In the flowchart in FIGS. 4 and 5, the processing in steps
S3 through S6 corresponds to the above-described liquid level
control, and the processing in steps S7 through S10 corresponds to
the above-described pressure control.
[0114] While the control of the inverter circuit 22I by the control
device 90 has been described above, when the electrolysis of HF is
started, the control device 90 controls the inverter circuit 32I
similarly as in the above-described processing in steps S7 through
S10.
(5) Effects
[0115] (5-a) In this fluorine gas generation device 100, the
control device 90 carries out the liquid level control. Therefore,
even when the liquid level of the electrolytic bath 5 in the anode
chamber 4 becomes higher than the reference level, the liquid level
is adjusted to fall to the reference level or below. The
fluctuations in liquid level of the electrolytic bath 5 are
restricted in this manner.
[0116] Further, the liquid level control is adjusted by changing
the rotational speed of the motor 22M of the compressor 22. This
eliminates the need to adjust the discharge pressure of the
hydrogen gas in the hydrogen gas discharge pipe 20 through the
operations of opening/closing the control valves 21, 23, 31, 33. It
is thus unnecessary to perform maintenance due to the early
deterioration of the control valves 21, 23, 31, 33, and the number
of times of maintenance work decreases. This results in a reduction
of the maintenance cost of the fluorine gas generation device
100.
[0117] (5-b) Further, in this fluorine gas generation device 100,
the control device 90 carries out the pressure control in addition
to the liquid level control. This restricts the fluctuations in
pressure inside the cathode chamber 3 and the anode chamber 4,
while restricting the fluctuations in liquid level of the
electrolytic bath 5. As a result, the fluctuations in electrolysis
conditions upon electrolysis of HF are restricted.
[0118] (5-c) The liquid level control and the pressure control are
carried out by changing the rotational speed of the motor 22M by
controlling the inverter circuits 22I, 32I. Accordingly, compared
to the case of opening/closing the control valves 21, 23, 31, 33,
the discharge pressure of the hydrogen gas in the hydrogen gas
discharge pipe 20 and the discharge pressure of the fluorine gas in
the fluorine gas discharge pipe 30 can be adjusted readily and
finely. Therefore, even if the electrolyzer 1 is reduced in size,
the pressure in each chamber 3, 4 can be controlled with ease and
with precision. This enables downsizing of the fluorine gas
generation device 100.
(6) Other Embodiments
[0119] (6-a) In the above embodiment, the description was made
about the case of setting a common target pressure value U for the
cathode chamber pressure value and the anode chamber pressure value
for performing the pressure control. Not limited thereto, the
target pressure value (first target pressure value) set for the
cathode chamber pressure value and the target pressure value
(second target pressure value) set for the anode chamber pressure
value may differ from each other. In this case, for example, the
second target pressure value is preferably set smaller than the
first target pressure value.
[0120] Thus, by the pressure control, the cathode chamber pressure
value is adjusted to approach the first target pressure value, and
the anode chamber pressure value is adjusted to approach the second
target pressure value that is smaller than the first target
pressure value. Consequently, the pressure inside the cathode
chamber 3 becomes higher than the pressure inside the anode chamber
4. This prevents the liquid level of the electrolytic bath 5 in the
cathode chamber 3 from rising beyond the liquid level of the
electrolytic bath 5 in the anode chamber 4.
[0121] For example, the first target pressure value is set to 100
kPa in absolute pressure, and the second target pressure value is
set to not less than 95 kPa and not more than 99 kPa in absolute
pressure.
[0122] It is noted that the first and second target pressure values
may be set as appropriate in accordance with the volumetric
capacities of the cathode chamber 3 and the anode chamber 4.
[0123] (6-b) As described above, in the fluorine gas generation
device 100 in FIG. 1, the liquid level sensor 40 for detecting the
liquid level of the electrolytic bath 5 is disposed in the anode
chamber 4. The control device 90 carries out the liquid level
control on the basis of the output signal from the liquid level
sensor 40.
[0124] Not limited thereto, in the case where the flow rate of the
fluorine gas discharged from the fluorine gas discharge pipe 30 is
not particularly determined, the liquid level sensor 40 may be
disposed in the cathode chamber 3. Further, the control device 90
may carry out the liquid level control on the basis of the output
signal from the liquid level sensor 40 disposed in the cathode
chamber 3.
[0125] FIG. 6 is a schematic diagram showing the configuration of
the fluorine gas generation device according to another embodiment.
In the following, the differences of the fluorine gas generation
device 100 in FIG. 6 from the fluorine gas generation device 100 in
FIG. 1 will be described.
[0126] As shown in FIG. 6, in this fluorine gas generation device
100, the liquid level sensor 40 is not disposed in the anode
chamber 4, but disposed in the cathode chamber 3. In the present
example, the control device 90 controls the inverter circuit 32I on
the basis of the output signal from the liquid level sensor 40
(liquid level control).
[0127] For example, in the case where the liquid level of the
electrolytic bath 5 in the cathode chamber 3 has become higher than
the reference level, the control device 90 causes the frequency of
the driving voltage generated in the inverter circuit 32I to be
increased by a prescribed value with respect to the frequency at
that time point. This increases the rotational speed of the motor
32M included in the compressor 32, and increases the discharge
pressure of the fluorine gas discharged from the compressor 32,
whereby the pressure inside the anode chamber 4 decreases. As a
result, the liquid level of the electrolytic bath 5 in the anode
chamber 4 rises, and also, the liquid level of the electrolytic
bath 5 in the cathode chamber 3 falls below the reference
level.
[0128] In this manner, even when the liquid level of the
electrolytic bath 5 in the cathode chamber 3 becomes higher than
the reference level, the liquid level control is carried out on the
basis of the output signal from the liquid level sensor 40, so that
the liquid level is adjusted to fall to the reference level or
below.
[0129] (6-c) Not limited to the fluorine gas generation devices 100
in FIGS. 1 and 6, the liquid level sensor 40 may be provided in
each of the cathode chamber 3 and the anode chamber 4. The control
device 90 may carry out the liquid level control on the basis of
the output signals from the liquid level sensors 40 disposed in the
cathode chamber 3 and the anode chamber 4.
[0130] FIG. 7 is a schematic diagram showing the configuration of
the fluorine gas generation device according to yet another
embodiment. In the fluorine gas generation device 100 in FIG. 7, a
liquid level sensor 40 is disposed in each of the cathode chamber 3
and the anode chamber 4. In the present example, the control device
90 controls the inverter circuits 22I, 32I on the basis of the
output signals from the respective liquid level sensors 40 (liquid
level control).
[0131] In this manner, even when the liquid level of the
electrolytic bath 5 in the cathode chamber 3 becomes higher than
the reference level, the liquid level is adjusted to fall to the
reference level or below. Further, even when the liquid level of
the electrolytic bath 5 in the anode chamber 4 becomes higher than
the reference level, the liquid level is adjusted to fall to the
reference level or below. It is thus possible to restrict the
fluctuations in liquid level of the electrolytic bath 5 in the
cathode chamber 3 and the anode chamber 4.
(7) Correspondences between the Elements Recited in the Claims and
Those Described in the Embodiments
[0132] In the following paragraphs, non-limiting examples of
correspondences between various elements recited in the claims
below and those described above with respect to various preferred
embodiments of the present invention are explained.
[0133] In the embodiments described above, the hydrogen gas is an
example of the first gas, the fluorine gas is an example of the
second gas, the cathode chamber 3 is an example of the first
chamber, the anode chamber 4 is an example of the second chamber,
the hydrogen gas discharge pipe 20 is an example of the first gas
discharge path, and the fluorine gas discharge pipe 30 is an
example of the second gas discharge path.
[0134] Further, the liquid level sensor 40 is an example of the
liquid level detector, the compressor 22 is an example of the first
pump, the motor 22M is an example of the motor of the first pump,
the inverter circuit 22I is an example of the first inverter
circuit, and the pressure gauge PS1 is an example of the first
pressure detector.
[0135] Furthermore, the compressor 32 is an example of the second
pump, the motor 32M is an example of the motor of the second pump,
the inverter circuit 32I is an example of the second inverter
circuit, and the pressure gauge PS2 is an example of the second
pressure detector.
[0136] Further, the control device 90 is an example of the
controller, the control valves 21, 23 are examples of the first
open/close valve, and the control valves 31, 34 are examples of the
second open/close valve.
[0137] Furthermore, the target pressure value U is an example of
the first and second target values, the first target pressure value
is an example of the first target value, and the second target
pressure value is an example of the second target value.
[0138] As the elements recited in the claims, a variety of other
elements having the configuration or function recited in the claims
may be used as well.
INDUSTRIAL APPLICABILITY
[0139] The present invention is applicable to the generation of
gases by electrolysis.
* * * * *